CRYSTAL STRUCTURE OF AN ENOLASE (PUTATIVE GALACTARATE DEHYDRATASE, TARGET EFI-500740) FROM AGROBACTERIUM RADIOBACTER, BOUND NA and L-MALATE, ORDERED ACTIVE SITE
Characterized enzymes in the galactarate dehydratase III family catalyse the dehydration of m-galactarate to 2-keto-3-deoxy-galactarate, as part of the synthesis of alpha-ketoglutarate. They differ from previously characterised galactarate dehydratases in the enolase superfamily, utilising some unique catalytic residues. The characterised enzyme from Agrobacterium tumefaciens C58 has also been shown to convert D-galacturonate to 3-deoxy-D-xylo-hexarate or 3-deoxy-D-lyxo-hexarate, an unexpected reaction for an enolase superfamily member, as it involves abstraction of a proton alpha to an aldehyde group rather than a proton alpha to a carboxylate group.
Defined by 6 residues: ASP:A-189HIS:A-191GLU:A-216GLU:A-242ASP:A-265HIS:A-292